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finished my PCC88 preamp

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Hi @ll

I just have finished my PCC88 preamp. I have build it together with an Class-A-amp.
 

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Tyimo said:
Hi Till!

How do you like the sound???
What is the power stage circuit??? Maybe a schematic for the public??:)

Greets:

Tyimo

Hi Tyimo,

the sound is really good. It is a very good addition to a class-A amp like the Pass Aleph.

What do you mean with the power stage circuit? Do you mean the amp? This is similar to the Aleph.


greets Till



ilimzn said:
Not entirely on topic :) but where did you get the heatsinks?

Hi ilimzn,

the heatsinks are out of an old car-hifi-amp that I have had in the early 90s. The amp was realy bad so I stripped it and kept the heatsinks.
But you can get them here:

http://www.seifert-electronic.de


greets Till
 
Excuse the ignorance, is it similar to ECC88?
If so are you using anything to amplify the voltage a bit before the output stage? I love the "sound" of the ECC88, the implementation I have running now, is not coloured, although I'd admit it is slightly veiled in the midrange.

But what keeps eating me is that it basicaly runs at less than unity voltage gain, which probbly means the next stage is working even harder... also current output is pretty low

Sounds freakin nice though, not using it in the absence of anything better is not an option. One of my the locals I met through this site is peaking my interest in improveing/replaceing my valve buffer.

The only benifit I can see it is the nice input impendance... hard to imagine it has such a big effect though.
 
Hi Nordic,

the difference between the PCC88 and the ECC88 is that the PCC88 needs 300mA for the heating, the ECC88 needs 6.3V (or so).

Right now I am using the PCC189. It is based on the PCC88 and you dont have to change anything. Just Plug and Play. The sound is a bit "smoother" and "realistic" now. It sounds better for my ears.


I don´t know if there is a difference or benifit to an other preamp. I have only got a comparison to some other preamps with normal transistors. sorry for that



greets Till
 
Yep, sounds like they are similar... running 6V at 365mA on the heaters over here...

I only use one half of a valve to get my 2 channels, your implimentation seems to add more current by using both halves

I have 2 spare ECC88s, think I'll try your circuit as soon as I have cashflow for a small transformer again...think I used up all of mine now... and a few PSU caps.

Are the heatsinks just for show?
 
Roemhild said:
Hi Nordic,
the difference between the PCC88 and the ECC88 is that the PCC88 needs 300mA for the heating, the ECC88 needs 6.3V (or so).

Actually, most PCC88 can be used instead of ECC88 with no change - ECC88 use 6.3V heaters, while the PCC88 heater normally needs about 6.8-7V for 300mA, but because it's heater is made for series chains, it is very good at keeping nearly constant current even at lower or higher voltages. Because of this, a PCC88 will normally use about 280-290nA at 6.3V which is close enough, and corresponds to a slightly lower voltage heater, which may actually be benficial in other ways.

Right now I am using the PCC189. It is based on the PCC88 and you dont have to change anything. Just Plug and Play. The sound is a bit "smoother" and "realistic" now. It sounds better for my ears.

This is quite strange, really, as the PCC189 is a variable mu triode derived from the PCC88. Of course, how much the variable nature of the mu actually applies to your designe, depends on the bias point, you should check the curves. In any case, I'd stick with the PCC88.

Finally, thanks for the link to Seifert - I always have problems finding heatsinks with long fins, and they seem to have several that would fit my needs.
 
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